Why can't I lower my honeywell 8500 below 67 on cool?

First be sure the hole in the wall behind the tstat is sealed with putty or the like. This could be your issue due to negative pressure in the house. What you are describing may be something different, the unit should eventually catch up and satisfy if it was working properly. The house would just be cooler. There is a calibration feature that can change the room temp +/- 5 degrees but seal the whole and measure the return air temp vs the supply air temp AT the unit, NOT the grills.

What is the model # of this Honeywell thermostat?

Sounds like the Peltier effect elements have failed.


http://www.tetech.com/Peltier-Thermoelectric-Cooler-Modules.html


Depending on your handyman skills, you can change them yourself or have someone troubleshoot and change them.

am having the same problem, and same circumstance. Did you find a solution?

take shelves off. temp display unit in middle of shelf is where circuit board is for testing. pull middle unit forward and unscrew back panel. check lines for leak. color should look like a teal green. thats where your leak will be. Need tech. for the rest.......good luck!!!!

As to your question 'will 75 cool the house?' The answer is 'yes' - if the outside temperature is low enough. Typically speaking you can expect your central AC to cool a properly insulated house to a down to a temperature of about 20-25 degrees lower than the outside temperature. For example - if the outside temp is 95 degrees. You could expect to get your house down to 70-75 degrees. If the outside temp is 110 degrees then you could only expect to get the house to 85 or 90 degrees.

So .. as you can see - your 'inside' temp will be directly affected by the 'outside' temperature.

As to the operation of central air; it is very simple.

I would suggest that you not pay 'too much attention' to what you have the thermostat set on. A comfortable temperature - is a personal thing - so - I would set it somewhere - say 72 and see how I (and others in the house) was handling that setting.

If you want it 'cooler' just 'notch' it down a degree or two - if you need it a little warmer - turn it up a degree or two. Do this "fine adjusting" till you have the temperature setting you are comfortable with.

Usually the more you can leave your thermostat alone the better off you will be from a comfort position and an electrical useage standpoint. Obviously, the higher you have your thermostat set the 'less' it will cost you on your electric bill.

How high you set the temperature is a balance you have to come to based on how comfortable you want to be - matched with how much you want to hold down the electric bill.

hope this helps

Not sure, but did you clean the filter in the back? Ours has that, and the temp starts creeping up every few weeks until I clean it. But we've never been able to get it below 58 or so, and in the last year, not below 60. I think that's just the nature of this type of cooling. Our house is also at 80. But, can keep it at 60 with the above cleaning.

if you set the thermostat on 70 and your house won't get ant cooler than 72, there is a problem with your system,not your stat. I'm thinking you are low on refrigerant if it is somewhat working. when the unit is running, if you can get your hand on the larger refrigerant line under the black insulation, it should be cold, about 55 degrees.

make sure the system switch is in the cool position, then press run program button and allow a couple of minutes for system to cycle on, if it doesn't come on press the button for lowering the set point, set it to 72 degrees and then press the hold temperature key.

Check the drain line. Possibly tripped the float switch because the drain is clogged. Don't leave float switch out, you'll have to vacuum drain clear.

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